=== LGP Archive format for PC by [[User:Ficedula|Ficedula]] ===
This section explains how the LGP archives from FF7PC FF7 PC are constructed. There's probably no reason why If you'd need to know this (Plugre looking for a tool that already manages LGP archives, try [[User: Use my Ficedula|Ficedula]]'s [http://wwwsylphds.ficedulanet/f2k3/index.com html LGP Editor] !) but the file format might be useful to SOMEBODY.
Essentially the LGP file is split up into four (maybe less, depending on how you count it) sections.
# File terminator
==== Section 1: File Header ====
This contains two parts: A header of fixed size, then the table of contents.
The first item is 12 bytes containing the file creator. This is a standard string, except it is "rightaligned". In other words the blank space comes BEFORE before the actual text, not after. Oh: In FF7 it's always "SQUARESOFT" preceded by two nulls to make it 12 bytes. The only other thing you might see is the header "FICEDULA-LGP", which I use to indicate a file is an LGP *patch* one of my programs has constructed, not a complete archive.
Next is a four-byte integer saying how many files the archive contains.
Each entry in the TOC has the following structure:
{| borderclass="0" cellpadding="3" cellspacing="1" style="background: rgb(0,0,0)" align="centerwikitable"! style="background:rgb(204,204,204); width:80px;" align="center" | Offset! style="background:rgb(204,204,204); width:200px;" | Length
|-
|style="background:rgb(255,255,255);" | 20 bytes|style="background:rgb(255,255,255);" | Null terminated string, giving filename
|-
|style="background:rgb(255,255,255);" | 4 byte integer|style="background:rgb(255,255,255);" | Position in this file where data starts for the file
|-
|style="background:rgb(255,255,255);" | 3 bytes1 byte|style="background:rgb(255,255,204);" | Some sort of check code. File attributes? Normally seems to be<br />14,0,0 but it does vary. Unsure about this|-| 2 byte short| style="background: rgb(255,255,204)" | Something to do with duplicate file names. If a name is unique it is 0, otherwise it is assigned a value based on existing duplicates. (Hard to explain)
|}
Simple!==== Section 2: Section formerly designated as "CRC Code" ==== This section is 3600 bytes. It is 30 sets of 30 entries containing two 16-bit words each (30 x 30 x 2 x 2 = 3600) The sets contain file-group information which is based on the first two letters of each file name. The first letter, minus the value for ascii 'a' (0x61) is the index of the set to which the file belongs. The second letter, minus the value for ascii ' ' ' (0x60) is the index of the entry within the set. Since the second letter in all of the file names is ascii 'a' or greater, it means that the lowest entry index is 1, so the first entry (at index 0) in every group is always zero (0x0000). Each entry is two words. The first word is the 1-based index of the directory entry for the first file in the set.
==== Section 2: CRC Code ====The second word is the number of files in the set, most of which are 0x003c (60). There are a few entries after the bulk which have fewer entries.
This code is used to validate the LGP archive. The bad news is I have no idea how to make it (Imeaning of these sets and why they've figured out how to decode it, ie. find out whether the archive is valid ... but I can't create my own). The good news is you don't need to! The ONLY thing re divided in this CRC manner is based on is the number of files in the archive (maybe the filenames too ... haven't checked that). Anyway, the TOC is the only thing this check relates yet tobe determined. So if you're replicating an archive from FF7 for use in the game with the same number of files and filenames (and what ELSE would you use LGP archives for?) you can just copy the CRC section from an existing file. Cheap but effective :)
Normally it's 3602 bytes long. I think There is one archive was different? Maybe MAGIC.LGP 16- can't remember. Anyway, one normally-safe way bit word with the value of calculating the CRC size is to find 0 (0x0000) at the end of the TOC and the beginning of the first file. Anything in between is probably CRC code. (Not guaranteed this data which may belong to work! It works with "official" archives but editors - such as mine - can screw around with this section or the TOC to achieve extra things)next.
==== Section 3: Actual Data ====
The data from the files. However it's not that simple: the TOC doesn't list how long each file is (somewhat useful!). It's done here. The offset in the TOC is actually the position of yet another file header. Format is:
{| borderclass="0" cellpadding="3" cellspacing="1" style="background: rgb(0,0,0)" align="centerwikitable"! style="background:rgb(204,204,204); width:80px;" align="center" | Size! style="background:rgb(204,204,204); width:200px;" | Description
|-
|style="background:rgb(255,255,255);" | 20 bytes|style="background:rgb(255,255,255);" | Null terminated string, giving filename
|-
|style="background:rgb(255,255,255);" | 4 bytes|style="background:rgb(255,255,255);" | File length
|-
|style="background:rgb(255,255,255);" | Varies|style="background:rgb(255,255,255);" | The file data itself
|}
Simple!==== Section 4: Terminator ==== After the last piece of data comes the file descriptor. This is a simple string, except instead of being null-terminated it's terminated by the end of the file. It's "FINAL FANTASY 7" for all archives, except LGP patches, where it's "LGP PATCH FILE".
==== Notes ====
==== Section 4: Terminator ====The game is remarkably flexible about LGP archives. So long as the TOC and the CRC data is intact it'll accept just about anything.
After * Example 1: The filename in the last piece of data comes TOC and in the actual file descriptorheader don't have to match. This is a simple string, except instead of being null-terminated It only checks the TOC.* Example 2: You can point two entries in the TOC at the same data and it's terminated by works.* Example 3: You can have ANY junk in the end of data section so long as all the TOC entries point to a valid fileheader. It's Not every piece of data has to be "FINAL FANTASY 7accounted" for all archives, except LGP patches, where it's "LGP PATCH FILE"by the TOC. There can be data not used.
==== Notes ====[http://www.ficedula.com/ LGP Editor] uses this to its advantage in the Advanced Editor. If you want to replace a file in an LGP archive with your own copy, it just puts the file on the end of the LGP, writes a new file terminator, and updates the TOC to point at the new file. It even lets you link two TOC entries to the same data or have "inactive" files in the archive that aren't referenced by any TOC entry.
I don't know whether the file terminator has to be intact, but for safety's sake my editor preserves it. The game is remarkably flexible about LGP archivesCRC must be present and correct. So long as Also, if you're replacing an archive with you're own custom version make sure it has filenames in the TOC and matching the ones in the CRC data is intact it'll accept just about anythingold one.
* Example 1: The filename in the TOC and in the actual file header dongame doesn't have to matchcheck archive sizes as long as all filenames are present. It only checks So if you want, you could replace an archive containing 95 files with a 98-file archive, so long as 95 of those 98 names matched those present in the TOCoriginal 95-file archive. * Example 2: You can (However there's no point two entries in doing this when the TOC at game won't use any files other than the same data and 95 it works. * Example 3: You can have ANY junk in the data section so long as all the TOC entries point 's expecting to a valid file header. Not every piece of data has to be "accounted" for by the TOC. There can be data not usedfind).
My LGP Editor uses this to its advantage in the Advanced EditorThere are reports on [http://forums.qhimm. If com/ Qhimm's board] that once you want to replace a file in 've altered an LGP archive with your own copyand the game refuses to read it, it just sticks the file on the end of won't ever read it until you reinstall - even if you fix the LGP, writes problem/restore from a new file terminatorbackup. The idea was generally scorned and ignored, and updates the TOC but I'll mention it because something like that happened to point at the new file. (Advantage: Fast)me. It even lets you link two TOC entries to the same data :) or have "inactive" files in the archive that aren't referenced by any TOC entryNo solid conclusion can be drawn here.
I Sometimes, there are data "gaps" in the file that don't know whether the file terminator has appear to be intact, but for safetyreferenced by any file - even by an inactive file. If you's sake my editor preserves it. The CRC DEFINTELY has re only using the TOC method to be present and correctget at files (the easy way) then you won't notice this anyway. AlsoHowever, if you're replacing an archive stepping through the file header by header, even reading the unused ones, this can cause problems. If you use my program to update a file with youone that're own custom version make sure s smaller than the original (can happen) then it writes it has filenames in , but leaves a gap after it (of course). However, to help you out, after the TOC matching end of the file, it writes a 4 byte integer saying how much more space to skip over to reach the ones in next file header. This really doesn't affect many things - only tools (like my Advanced LGP Editor) that bypass the old one, ne?TOC to construct their own file lists. FF7 never notices a thing.
Oh: The game doesn't check archive sizes so long as all filenames are present. So if you want, you could replace an archive containing 95 files with a 98-file archive, so long as 95 of those 98 names matched those present in the original 95-file archive! (There's no point in doing this - after all, the game won't use any files OTHER than the 95 it's expecting to find).=== Useful downloads ===
Other point: I've heard reports on Qhimm's message board that once you've f***ed an archive and the game refuses Below there are links to read it, it won't EVER read it until you reinstall - even if you fix the problem/restore from a backup. The idea was generally scorned and ignored, but I'll mention it because something like known programs that happened are capable to me. Then again, it COULD have been because I upgraded basically everything in my PC; so no solid conclusion to be drawn here.edit LGP archives:
Further point* [http: (due to changes in my //www.sylphds.net/f2k3/programs/lgptools/lgptools160.zip LGP Tools] - with an Advanced LGP Editor allowing edit archive thoughoutly* [http:/Cosmo programs) Sometimes, there are data "gaps" in the file that don't appear to be referenced by any file /elentor.com/Projetos/FF7- even by an inactive fileTools/Extracting/Emerald. This happens due to the way my programs update archiveszip Emerald] - has mass extracting/repacking function* [http://mirex. If you're only using the TOC method to get at files (the easy way) then you won't notice this anywaymypage. However, if you're stepping through the file header by header, even reading the unused ones, this can cause problemssk/index. If you use my program to update a php?selected=1#Unmass Unmass] - general file extractor with one that's smaller than the original (can happen) then it writes it in, but leaves a gap after it (of course). However, to help you out, after the end of the file, it writes a 4 byte integer saying how much more space to skip over to reach the next file header. This really doesn't affect many things - only tools (like my Advanced LGP Editor) that bypass the TOC to construct their own file lists. FF7 never notices a thing.archives support
